ARTÍCULO CLÍNICO

 

MG-OSSEOUS implants. A multicentric retrospective study

Los implantes MG-OSSEOUS. Estudio multicéntrico retrospectivo

 

 

E. Serrano Caturla¹, R. Martín-Granizo López²

1 Cirujano Oral y Maxilofacial. Médico Adjunto del Servicio de Cirugía Oral y Maxilofacial del Hospital General de Vic, Barcelona.
Médico Adjunto de Urgencias del Servicio de Cirugía Oral y Maxilofacial del Hospital Vall d’Hebron, Barcelona, España
2 Médico Adjunto. Servicio de Cirugía Oral y Maxilofacial. Hospital Clínico San Carlos. Madrid. España

Dirección para correspondencia

 

 

 

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ABSTRACT

Objective. We present some statistically contrasted results regarding the survival and incidences of MG-OSSEOUS implants and prosthetic components (Mozo-Grau, S.L., Valladolid, Spain), and we prove that they have the same efficacy when compared with other commercial implants.
Material and methodology. This is a retrospective multicentric study coordinated by a company called Scientific Management in O&SS (Barcelona, Spain). 1001 dental implants were placed in 247 patients and 328 prostheses were designed between 2004 and 2005, with a follow-up of two years. All implants were loaded with prostheses. We detail and analyze each implant, according to the diameter, length, position, surgical timing, loadings, design and types of prostheses and complementary surgical procedures, either synchronic or metachronic.
Results. After the statistical method was homogenized, we were able to report an overall implant survival rate of 97.8% with monitoring of two years. The failures depending on the peculiarities of each clinical case are provided. No prosthetic failures are reported.
Discussion. The criteria and indications applied by the professionals to the MG-OSSEOUS implants are standardized depending on the clinical case. Our results are compared with the international scientific literature, past and present, with these procedures totally agreeing with those found in the history of implantology. Finally, our survey is compared with those published by the Branemark team.
Conclusion. The mixture between the quality of the MGOSSEOUS implants and the scientifically supported criteria regarding the implants, reveals an implant failure of 2.2% over two years, with a survival of 100% of both the replaced implants and the loaded prostheses.

Key words: Dental implants; MG-OSSEOUS; Retrospective studies; Criteria in implantology.

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RESUMEN

Objetivo. Aportar unos datos estadísticamente fiables sobre la supervivencia e incidencias asociadas a los implantes y prótesis del modelo MG-OSSEOUS (Mozo-Grau, S.L., Valladolid, España) y demostrar que su eficacia es comparable a todas las marcas comerciales.
Material y método. Estudio multicéntrico retrospectivo coordinado por la empresa Scientific Management in O&SS (Barcelona, España). Se colocaron 1001 implantes en 247 pacientes y se diseñaron 328 prótesis, entre los años 2004 y 2005, con un seguimiento de 2 años. Todos los implantes cargados. Se analizan y pormenorizan todos los implantes, por diámetros, longitudes, posiciones, fases quirúrgicas, cargas, tipos y modelos de prótesis y técnicas complementarias aplicadas, tanto sincrónica como anacrónicamente.
Resultados. Tras la homogeneización de las muestras, se objetiva una supervivencia del 97,8% a los 2 años, detallando los fracasos según las características de cada caso clínico. No se reporta ningún fracaso de la prótesis.
Discusión. Protocolizamos una serie de criterios e indicaciones a la hora de colocar los implantes MG-OSSEOUS según los casos clínicos. Comparamos nuestros resultados con la bibliografía, tanto pretérita como actual, coincidiendo con la manera de actuar a lo largo de la historia de la implantología. Finalmente, extrapolamos los resultados que consideramos comparables a los publicados por el grupo Branemark.
Conclusión. La calidad del implante MG-OSSEOUS combinada con protocolos implantológicos científicamente contrastados, muestra un 2,2% de fracaso a los 2 años de seguimiento, con un porcentaje de éxito del 100% tanto en la recolocación del implante como en la fase protésica.

Palabras clave: Implantes dentales; MG-OSSEOUS; Estudio retrospectivo; Protocolos implantológicos.

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Introduction

Implantology, as seen today, does not resemble its origins at all, thanks to Professor Branemark. No one remembers the problems that arose; constant replacement of implants, complaints from dentists who at first did not treat these cases, not to mention the implant survival criteria. Neither do we stop to think about the initial difficulties in collecting data+ and classifying it. In the world of implantology we have to thank Dr. George Zarb, to a large extent, a Canadian, without whom osseointegration would not be known on a worldwide scale.¹

The objective of this paper is to provide statistically reliable data on the survival and incidences associated with the MG-OSSEOUS model of implants and prostheses (Mozo- Grau, S.L, Valladolid, Spain), placed between 2004 and 2005 and with a follow-up of two years.

These implants are self-tapping, with a Branemark-type external hexagon and they have a RBM surface (resorbable blast media). This is altered with biocompatible media (calcium phosphate ceramics), which contains completely resorbable elements permitting removal after carrying out the process for altering the surface. The result is a titanium surface that is pure, clean and textured.

As the process for altering the surface does not entail using acid-etching, the surface of RBM implants is by definition free of any residues from acid-etching. Neither is it susceptible to titanium grain boundary degradation that can occur during aggressive acid etching procedures.^2-4

Many commercial brands have reported their studies on implants, but there is a great mixture of studies, results and methods in the scientific literature that do not permit the homogenization of conclusions, although these have always been based on favoritism by the company. It would appear that there are no objective statistical parameters to measure results in implantology, but this might be because their application is not of interest.

A study group from the Department of Oral Health Policy and Epidemiology and the Department of Oral and Maxillofacial Surgery of the Harvard School of Dental Medicine, headed by Dr. Chuang, defended the formulas that are statistically complex such as the Kaplan-Meyer analysis, or the use of the marginal approach of the semiparametric survival methods, in order for the results to be objective and for conclusions to be reached with no bias or mistakes.^5-7 It would be correct to say that it is true that these statistics cannot be grasped by the vast majority of implantologists and that, as a result, the assistance of an epidemiology and statistics department is required.

Our retrospective study is clean and clear. In order for this to be a reliable study, protocol and data collection have been rigorously carried out and the analysis of the statistics has been exhaustive.

 

Material and Method

The study was carried out by a specialized company, Scientific Management in O&SS, (Barcelona, Spain) which was entrusted with everything from the initial design to the final treatment of the results.

The study was multicentric and various professionals from different clinics took place, all selected by the same person. Their professional expertise was taken into account and the stipulated protocol was strictly followed. Before the study, a protocol was designed and all the professionals involved in the study agreed to follow it. They had no ulterior motives and the procedures were carried out during their working day. None of the collaborators collecting the data had to vary their method of placing implants or fitting the prostheses onto the implants.

Together with the protocol, an exhaustive questionnaire was drawn up for the study, which was easy to fill in, and data from the clinical histories was collected so that none were lost (Fig. 1).

As this was a multicentric study, the statistical parameters were lowered so that homogenizing the different groups was possible. Calculations were applied for the mean age deviation of the patients taking part, as well as the length and width of the implants placed by each of the professionals. With this data of the different subgroups of the patient samples in the study, the typical variance and deviation was calculated, and techniques were finally applied for the comparison of samples by means of homogeneity tests (chi square test). Favorable results were obtained that permitted homogenizing groups so that any slant in the selection and treatment of data was cancelled out.

Two people put the results together of the questionnaires once collected. These were interchanged in order to detect any data collection errors. Only one professional from the implantology sector set out and dealt with the results putting emphasis on handling them correctly.

With regard to data collection, only two main incidents were encountered. The first was that during complete restorations, especially of the maxilla, sometimes the position of the implants was not filled in. As a result, depending on the number placed into the same maxilla, numbers for the dental positions were assigned, that were never uncertain. There was a scientific base, and we were aware that the fixed complete restorations included crowns from second molar to second molar.

The second statistical occurrence related to the ages of some of the patients that were not filled in. As this was not relevant for the final result, because the quality of bone was sufficiently homogenous, ages were assigned of between 55 and 60, given the statistical inference of the rest of the ages of the patients.

Only four questionnaires were rejected because the lack of sufficient information did not permit the extrapolation of data, such as single implants with no given position. Of these, only six were rejected with regard to the total number of implants.

The study sample is defined as the number of implants placed. The number of patients with implants and the number of prostheses fitted are only quotients for obtaining the required results.

 

Results

A total of 1001 MG-OSSEOUS implants were placed in 247 patients (51.4% females), with a female/male quotient of 1.06/1. The ages of the patients varied between 18 and 80, and the average age was 57.8. The implants placed in a single surgical procedure represented 31.76%, of which 97% were in the mandible. For the remainder, the technique of leaving the implants submerged under the gingiva was used and, after a period of 3 to 6 months depending on the area of the jaw, a second surgical procedure was carried out to connect the healing abutments.

Delayed loading was used for 91.42% of the implants. Only in 2.19% of cases was+immediate loading used. In all cases, evidently in the mandible, for design of complete prosthesis with metal-porcelain crown (7.9% of all complete crown prostheses). For the remainder immediate loading was used, and always the same type of prosthetic design, previously mentioned, was used.

Post-exodontia implants represented 2.89%, with an exhaustive control of the indication, and as a result no failures were reported. Only 13 transmucosal implants were placed (1.29%), all in the maxilla. The commitment of the patients was used as criteria, on which secondary effects had to be minimized.

The distribution of the implants according to diameter and quadrant (Fig. 2) and their distribution according to quadrant, are shown in the graph together with the specific position of the teeth (Fig. 3). The diameter and length of the implants used are reflected in figure 4, which shows that the implants most used were those with a width of 3.75 mm and a length of 15 mm and 13 mm.

Fifty-one graft procedures were carried out (Fig. 5), that involved 116 implants (11.58%). Of note were 101 carried out together with sinus elevation, 77 of which were simultaneous with a mean elevation of 7.6 mm.

A total of 328 prostheses were designed, and no failures were reported. The planned distribution of the prosthesis types is shown in figure 6, together with the systems for fixing these (Fig. 7).

The survival of these implants after a two-year followup, and all loaded, was 97.8% and there was an implant failure rate of 2.19%. The motives for the failures are specified in figure 8.

 

Discussion

In this study a series of protocols were drawn up and applied by the excellent professionals participating in the study. This permitted a series of very interesting conclusions to be extracted. The first highlights the high quality of MG-OSSEOUS implants with RBM surfaces. The results from the followup of one-and-a-half to two years can be compared with those of other top brands that differ in design as well as in the way their surface is treated. They are simple to use and their diameters and lengths are versatile, as are the healing abutments, which make them ideal for positioning them in crestal bone, supracrestal positions, wide and narrow crests and anterior aesthetic sections. The presence of these two upper mechanized threads, allows for the soft gingival tissues in supracrestal locations to remain unaffected, as these adhere by means of hemidesmosomes to this surface, and inflammation is in this way avoided.

The next conclusion concerned immediate loading, so much in vogue these days and with very good results in the literature. This was shown to be a risky procedure that could directly influence the prognosis of the implant in the short or medium term. The criteria applied and reflected in this retrospective study, showed uniformity with the criteria previously applied by Ledermann, Schroeder y Babbush between 1979 and 1986 respectively.^8-10

Immediate loading was used for the implants placed in the mandible, but avoided in the maxilla. This led to a prosthetic and implant survival success rate of 100%. Many authors defend immediate loading in any part of the mouth, even occlusal, but we believe that the protocol adapted by our professionals, with such good results, is the most suitable.^11-14

The postextraction implants in our series, while limited, also had a 100% success rate over these two years. The success of this technique depends on the indications made by the professional when evaluating the quality of the remaining bone, and the presence or not of active periodontal disease that may compromise the survival of the implants. The results agree perfectly with those in the literature such as those in the Turkish article published in China, selected because of the similarity of the follow-up period for these implants, and in which there is no statistical difference between postextraction and delayed implants after a two-year follow-up.¹⁵

All the implants placed in a single surgical procedure were into the mandible, following the recommendations of many authors, as shown in this revision.¹⁶ A two-stage surgical protocol was decided for the maxilla, and the implants were uncovered at four to six months, as is recommended for bones with little density or that are thin, and for procedures associated with grafts.¹⁷

The professionals carrying out this study advocated a series of criteria when placing the implants, depending on the bone found in each patient, which for obtaining the success rates mentioned previously seems quite correct. The most used implant was the one with the standard diameter of 3.75 mm. It would appear that the professionals have given the right importance to the remaining bone crest, making the most of the crestal thickness, in order to avoid very fine peri-implant walls that could lead to bone necrosis or to implant failure. Implants with a wide diameter were not the most used option, not even at the back of the jaw, in order to avoid overheating the bone during drilling, especially with Type I and II bone in Lekholm and Zarb’s classification.

When there was little bone thickness, an implant that was as long as possible was chosen, and implants that were excessively short were avoided, even though they may have been narrow (3.4 mm).

During the average 1.5 year follow-up of the prostheses loaded on implants, no prosthetic failures were reported. The use of the screw prosthesis versus a cemented prosthesis seems to have depended more on the skills and preferences of the prosthodontist, than on local occlusal or vertical dimension requirements. This in fact seems to be a parameter that does not appear to influence prosthetic survival, unless poor criteria and assessment of the vertical dimension leads to chronic occlusal trauma of the prosthesis and the implants, leading to failure.

We have considered as implant failure the falling away of the implant, that is to say, the need for removing the implant because of a lack of stability. In the current literature there are many references to implant failure and especially to peri-implantitis involving excessive vertical bone loss of more than 4 mm in the first year and 1.5 mm the following year.^18-19 In our study we have not taken into account these criteria, as it is very difficult for various professionals to be objective on the same number of millimeters of vertical bone loss, while being in agreement on the same anatomic reference points on the crest. Our data collection would incur in serious statistical bias.

The implant failure rate of 2.19% reflected in this retrospective multicentric study, which has a loaded implant survival rate of 97.8% after a follow-up of two years, tallies perfectly with the studies and results published in the literature. One of the more relevant studies published in 2004 included a table of the Branemark group, which showed the survival of implants of different groups and studies (without taking into account the statistical peculiarities of each of them) (Table 1). In view of the quality of MG-OSSEOUS implants and the results of this retrospective multicentric study, we can show today, while lacking scientific rigor but with statistical extrapolation and inference of percentagestime, that the survival rate of MG-OSSEOUS implants at 5 to 10 years will be within the parameters published by important implantological groups on a world scale.

 

Conclusions

The results obtained in this retrospective study, with regard to the survival of MG-OSSEOUS implants, are within the range of all those published in the scientific literature, and as a result there in no disparity in performance.

In addition to the excellent quality of the implants, the success is due to proper planning of the surgical and prosthetic cases. This permitted an implant success rate of 97.8%, which was 100% after the failed implants were replaced, and 100% success rate for the prostheses, after a followup of two years.

No risky techniques were used, nor were excessively short implants placed, nor was impossible maxillary loading car ried out, as appears in the literature, rather a series of guidelines and protocols were followed, and this led to the success of the procedures. Implant and prosthetic survival was not distorted as a result of unreasonable indications.

 

Acknowledgements

Dra. Abarrategui López, Josune; Dres. Blanco y de Paz; Dr. Conrado, Andrés; Dra. Couto Fernández, Mª Dolores; Dr. Larumbe Aguirre, Alfonso; Dr. Ferreras Granados, José; Dr. Gutiérrez de Guzman, Fernando; Dra. Izquierdo, Marta; Dr. Martelan; Dr. Martín-Granizo, Rafael; Dr. Pazos Lameiro, José Antonio; Dr. Rojo Alonso, Rafael; Dr. Sarobe Oyarzun, Fco. Javier; Dr. Torrent Vicent

 

 

Dirección para correspondencia:
Eduardo Serrano Caturla
Gran Vía de Carles III 58-60 escalera A,
ático 1ª - 08028 Barcelona, España
Email: 31188esc@comb.es

Recibido: 08.05.06
Aceptado: 06.10.06

 

 

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